/Engine/Source/Runtime/MeshDescription/Public/MeshDescription.h
Populate the provided array with a list of edges which are internal to the polygon, i.e. those which separate constituent triangles.
template<typename Alloc> void GetPolygonInternalEdges ( const [FPolygonID](API\Runtime\MeshDescription\FPolygonID) PolygonID, [TArray](API\Runtime\Core\Containers\TArray)< [FEdgeID](API\Runtime\MeshDescription\FEdgeID), Alloc > & OutEdgeIDs ) const